Interior Surfaces

Here's a simple one, which I can't figure out and is doing my head in... How do I export objects which show the interior surface of a shape I've cut up? I created a ring, and cut the concaved outer side away, in order to get the convex inner side, but because this is the inside of the shape, it seems to be invisible.

Comments

You probably have the scene set to not show backfaces? Facets have two sides - the "normal" shows outwards, so when you cut away the outer ring, you exposed the backs of the inner ring.

To see these facets, select show/hide back faces - the fourth icon (looks like a cylinder) at the very bottom right side of the screen.

You can export at whatever export format you need - the most universal is .obj. You may or may not have problems rendering a texture you put on it, depending on the renderer - Carrara and Daz Studio have no problems with this.

However, I can't seem to export the .OBJ so that it shows the back-facing surface. In Poser, the disected ring that I made only shows the surface that faces forward, at the part of the ring that is furthest from the camera (the back).

I've tried adding volume to the disected ring, as well as putting a UV map on it.

When I mentioned you may have problems rendering, I had Poser in mind - not because I know anything about it, but having read here over the years that Poser handles normals differently.

I only have Poser Debut, because it was free and I was curious, but very seldom make use of it:) There are apparently some settings on export and import that you have to do - hopefully someone who has more knowledge of Poser than I can help out here.

If you add thickness on the outside, that should work. I just tried that in Debut and had no problems seeing and rendering all surfaces - just be sure to choose the "outside" option when adding thickness.

Thanks to youse guys for helping. When I added thickness, I did it to the interior... duh!

Mr RoyGee, I love you. No, really.

Sir Afreaginname, name your price. The "dirty" way did the trick.

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@afreaginname - interesting about making the polys double-sided. Does this mean you can give a different texture to each side? The only app I have come across that has this capability is Anim8or - but that doesn't carry over into other renderers. Does the UVMapper method do this - don't suppose that function is available in the Classic version?

interesting about making the polys double-sided. Does this mean you can give a different texture to each side?

Yup!! :)

The only app I have come across that has this capability is Anim8or - but that doesn't carry over into other renderers. Does the UVMapper method do this - don't suppose that function is available in the Classic version?

Rats...my elitist butt keeps forgetting I have the pro version...I just downloaded the classic and it doesn't have the "make two sided" option in it. My apologies to all.

By "not carrying over into other renderers", I'm guessing you mean that some renderers can't handle doublesided planes very well, which could very well be the case. I know that adding transparency to doublesided meshes screws up poser's renderer big time! :)

Making a mesh doublesided simply doubles the number of faces (and texture vertices, if mapped). The simplest mesh is defined as a list of vertices followed by a list of faces. If you make them doublesided, anim8or/uvmapper simply copies the list of faces, flips the normals, then adds this new list of faces to the previous list of faces.

Now one problem here is "UV separation". When a mesh is UV mapped, the map tends to fill the UV plane. The new faces will inherit the existing UV map and will overlay the same UV plane. Since all the faces share the same vertices, separating the 2 sides is virtually impossible.

So before adding doublesidedness, the UV layout should be squeezed over to fit on, say only the left side of the UV plane. That way, when you add doublesidedness, a new UV layout will pop up on the right hand side of the plane. Then you'll be able to apply different texture maps to each side.

When i was using Anim8or, I only ever used straight colours on each side, so never ran into the UV mapping problem. When it is coloured on both sides and brought into Carrara for rendering, Carrara ignores the "other" side. Fenric has developed a plugin for Carrara that gives it the ability to colour two sides - i don't have it and have not yet seen any queries regarding UV mapping problems, so guess all users only use simple colours or procedural shaders.

Very interesting subject and glad to have found a technical explanation for the function:)